AutoKernel by Scott Hunter is a modified C64 kernel ROM that will auto load and run the first BASIC program on device 8 when the computer is turned on.  This would be a great alternate kernel for something like the Ultimate64, unfortunately this would leave you without JiffyDOS.

Also included is a program by Ray Allen called SnappyLoader which is a BASIC menu that can be run by AutoKernel to assist in loading other programs.